The use of external structurants for providing rheological benefits to fluid detergent compositions is known. Examples of desired benefits include particle suspension, shear thinning properties, a thick appearance on the shelf, as well as stabilization of materials which are desired to be incorporated within the composition. See e.g. U.S. Pat. No. 6,855,680 to Smerznak et al. and U.S. Patent Appl. No. 2005/203213 to Pommiers et al.
Known external structurants include those such as those derived from castor oil, a fatty acid, fatty ester, or fatty soap water-insoluble waxes. These external structurants have been reported to be useful at levels of from about 0.1% to 10% by weight. One problem encountered with some of these external structurants is their sensitivity and susceptibility to degradation by conventional liquid detergent ingredients like detergent enzymes such as lipase enzyme. Additional problems encountered with many known structurants is that a certain amount of water that must be incorporated with such structurants in raw material form, increasing transportation cost and processing complexities; difficulties forming liquid having the properties of gel, such as a shear thinning gel, a gel capable of suspending particles, and/or a thixotropic gel. In certain instances thixotropic gels may be desired for localized delivery of a liquid detergent composition. Another problem encountered with known structurants is obtaining the desired rheological properties in a liquid while using relatively low amounts of structurant.
Thus, there remains an ongoing search for external structurants which can provide the desired rheological benefits to liquid detergent compositions which are less susceptible to degradation by conventional liquid detergent ingredients such as detergent enzymes. Moreover, in view of the increasing consumer demand for sustainable products, it would be desirable to provide improved detergents which lessen consumption of surfactants. The addition of detersive enzymes such as lipase have been reported to provide some cleaning benefits. These detersive enzymes, however, are capable of breaking down many different compounds, including in some cases known structurants. Thus, there remains a need for structurants that can provide a desired structure without excess amounts of water or solvent, and/or are not unduly sensitive to enzyme degradation.